European chafer beetles have eyes on local lawns
Those who love their lawn put a lot of time and effort to keep up lush appearances.
But in the battle against the invasive European chafer beetle, which savours the taste of grass roots, one of the best combat tools actually requires less effort, not more.
University of B.C. entomologist Rana Sarfraz said the half-inch beetle, originally from Europe, was first detected in New Westminster in 2001.
He explained that since they are outside of their natural range, there are few natural enemies around locally.
And that’s bad news if you like your lawn.
But fear not, Sarfraz said, because there are steps you can take now to avoid a future headache.
Adults begin to emerge in late May, and continue to appear through June and July.
They prefer to lay eggs where the grass is relatively short, and Sarfraz said a simple and effective way for homeowners to keep the pest away is by maintaining their grass at between seven and nine centimetres, or in the neighbourhood of three inches.
After adults lay their eggs, the newborns emerge as small larvae, known as grubs, which are C-shaped, light-coloured, and voracious.
These grubs remain near the surface of the soil, where they can munch on the grass roots through the winter and into spring.
Since they are so shallow in the ground, their wriggling serves as a real attention-grabber.
Birds and raccoons feast on these grubs, and can turn a lawn completely upside down in the process by digging them up.
There are a few options available in the fight against the chafer beetle.
Converting your classical lawn garden into a vegetable garden has served as a reliable control method since chafer beetles prefer grass roots, Sarfraz said.
But for those who insist on a nice green lawn, Sarfraz said there are some methods that don’t work at all.
Some have tried spraying pepper, and others have spread shiny objects like blank CDs and DVDs on their lawn, hoping the reflected light from the sun will deter birds.
What has proven as effective is watering one’s lawn with parasitic nematodes, but this requires good timing and a true neighbourhood effort.
These harmless microscopic worms rely on water to travel through the soil, and find their way onto the grubs, eventually attacking them from the inside. After sprinkling lawns with water containing the nematodes, the lawns must be kept moist for a least a week, to give the nematodes a route to travel.
The challenge is that even if a homeowner does his or her part, a non-cooperating neighbour can lead to the adults laying eggs there the following year.
Sarfraz said chafer beetles are attracted to acidic lawns, so increasing a lawn’s pH level, such as through liming or fertilization, can deter them.
While the chafer beetle wasn’t reported in Richmond in 2009, that has since changed, with reports of infested lawns in both the eastern and western part of the city.
For more information about the chafer beetle, and specific steps on how to control them, visit the City of Vancouver’s website at tinyurl.com/ChaferBeetle
European Chafer Beetle
• invasive species from Europe first reported in the U.S. in the 1940s
• first detected in B.C. (New Westminster) in 2001
• about 1.2 centimetres long and main food is grass roots
• adults begin to emerge in late May; lay eggs in July
• the inch-long grubs feed on grass roots through the winter